[NLRS] Aircraft Scatter

[Dr. Gerald N. Johnson]

I think those that advocate the exhaust as the reflector more than the 
aircraft don't expect the ionization to last nearly as long as the 
sometimes visible contrail which is condensed combustion products. Just 
that it should have a greater surface area than the aircraft. Fact is 
nobody is sure whether its the aircraft surfaces or the temporarily 
ionized combustion products or some of both. Most aircraft reflection 
research is based on pure reflection for monostatic radar not glancing 
because the official interest is in radar cross section where we are 
only interested in the minimum angle glance to get long range 
propagation. Since the reflector is not a uniform planar surface nor is 
it stationary we are going to get fading from multipath. We'd get less 
fading if it was a flat surface but then it would have to have the 
correct attitude and we get much better odds if its a bit rounded since 
its attitude is not there for our use its for flying passengers and/or 
cargo point to point. Fortunately the rounded surfaces make for less air 
friction and better wing lift. I suspect stealth aircraft can be seen 
quite well by widely spaced bistatic radar which is essentially what we 
are doing. That while they are shaped to minimize monostatic radar echo 
cross section that they have nice surfaces for aircraft scatter, unless 
the exposed surface is a good microwave absorber, such a detail is not 
easily found.

73, Jerry, K0CQ

On 12/14/2013 11:54 AM, Barry Malowanchuk wrote:
>
>
> I would be surprised if there were many good aircraft opportunities between  you and Gary..such a short path...the best is if you can find a plane that is on path between you. I did this in the 80s with VE5LY in Regina, on 1296.  He had a 45 el looper and 10 W from a 1271?, we worked for up to 10 min at a time, did it 3 nights out of 5 on a 737. It showed the  usual flutter which is not likely from the exhaust contrail
>
> Barry
>
> ----- Original Message -----
> From: "Bill Davis"<cqbilld at yahoo.com>
> To: "NLRS Reflector"<nlrs at mailman.qth.net>
> Sent: Saturday, December 14, 2013 9:43:57 AM
> Subject: [NLRS] Aircraft Scatter
>
>
>
>     The dongle based aircraft tracking thread is an interesting one, There are a number of aircraft tracking sites on the net, but they have in some cases a time delayed plot of the aircraft's position. I have at times tried to correlate the AC scatter enhancement on Gary W0GHZ's  signals with limited success.
>
>     On Gary's skeds it is VERY UNUSUAL to NOT see aircraft "effects" on his signals. It seems to be more common on 1296 and then 902. I wouldn't characterize the effects be enhancement, for often there is as much "nulling" of the signal as anything else.
>
>    Recently with the advent of the -20deg temps and low humidity, we have lost our 10GHz path from time to time. My memory may fail me, but I don't recall prior to the last couple of weeks seeing obvious AC enhancement on 10GHz. There has been 3 occasions over the last 2 weeks that Gary has been observed briefly 20db or more above the noise floor via AC scatter. In each case the enhancement did not seem to have obvious doppler. From that I assume the aircraft's path must have been at right angles to path? The enhancement as a result been VERY brief, 5sec or so.
>
>    It will be interesting to look for more favorable aircraft position to increase the signal enhancement period. There are a few flights that look promising. Real time tracking would be certainly more helpful than the current services.
>
>    After Christmas, I will investigate the real time tracking, looks interesting and CHEAP :-)
>
>   Merry Christmas and Happy New Year
>
>
> 73  Bill  K0AWU
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